Bearing bushing for universal joints

ABSTRACT

A bearing bushing for accommodating spider trunnions in bores in the shaft forks of a universal joint wherein the bushing has on one side a closed end for abutment of the end of the spider trunnion.

United States Patent [191 Kohler et al.

BEARING BUSHING FOR UNIVERSAL JOINTS Inventors: Hans-Joachim Kohler;Guido Rieder, both of Herzogenaurach, Germany Industriewerk Schaffler,Herzogenaurach, Germany Filed: Apr. 24, 1972 Appl. No.: 247,020

Assignee:

Foreign Application Priority Data May 7, 1971 Germany P 21 22 575.2

US. Cl. 308/35, 308/213 Int. Cl Fl6c 21/00, F16c 33/34 Field ofSearch..... 308/35, 174, 213, 212, 214;

[ Jan. 29, 1974 [56] References Cited UNITED STATES PATENTS 2,063,78712/1936 Brown 308/174 3,589,143 6/1971 Bott 308/212 PrimaryExaminerCharles J. Myhre Assistant ExaminerFrank Susko Attorney, Agent,or Firm-Hammond & Littell 5 7 ABSTRACT A bearing bushing foraccommodating spider trunnions in bores in the shaft forks of auniversal joint wherein the bushing has on one side a closed end forabutment of the end of the spider trunnion.

4 Claims, 1 Drawing Figure 1 BEARING BUSHING roR UNIVERSAL JJOINTS STATEOF THE ART Various forms of bearing bushings of this type have beenknown and used for a long time with good results. The bushings can bedesigned as sliding bearings or as bearings wherein a plurality ofrollers roll on the bore of the bearing bushing and on the surface ofthe trunnion of universal joint spider. One of the advantages of thelatter design is that the use of the rollers provides smoother operationwhich is desirable and is particularly favorable in universal joints.However, the trunnions of the spider of the universal joint bear in aslid ing fashion against the bottom or closed end of the bushing andthis produces a considerable degree of undesirable fri'ction. Onesolution to avoid this friction has been to provide an additional rollerbearing between the end face of the trunnion and the closed end of thebushing but this complicated solution is only suitable for very largebushings in massive universal joints.

The undesired friction between the end face of the spider trunnion andthe closed end of the bushing is particularly great since the parts areplaced under initial stress during the assembly of the universal joint.The initial stress is desirable to ensure free play during operation ofthe universal joint even over prolonged operation periods. Because o fthe possible total number of tolerances during assembly, it is possiblefor this initial stress betw een the end face of the spider trunnion andthe closed end of the bushing to become so great that the resultingfriction will become so great that it cannot be tolerated for practicalapplications.

OBJECTS OF THE INVENTION It is object of the invention to provide novelbearing bushing for universal joints to avoid excessive frictiontherein.

It is a further object of the invention to prevent excessive friction ina universal joint between the end faces of spider trunnions and thebearing bushing without additional mechanical means.

These and other objects and advantages of the invention will becomeobvious from the following detailed description.

THE- INVENTION The novel bearing bushing of the invention is comprisedof a thin-walled bushing drawn from sheet metal with one closed end toabut against the end face of a spider trunnion, the center of the closedend projecting inwardly toward the trunnion end face to form the soleabutment face even with the sagging of the center to be expected duringoperation.

This bushing embodiment solves the problem in two waysv First, thebearing bushing is made of thin-walled, sheet metal so that the closedend of the bushing can never bear against the end face of the trunnionwith excessive force during assembly even with unfavorable toleranceconditions because the closed end of the sheet metal bushing has arelatively flat spring characteristic and the force exerted by theclosed end on the end face of the trunnions will increase only slightlywhen the bushing is forced slightly too far into the bore receiving it.Secondly, compared to other bushings of the prior art, wherein thetrunnion end face abuts against the entire closed end of the bushing,the friction radius between the abutting surfaces is reduced since onlythe center of the closed end of the bushing abuts against the trunnionend face even allowing for the center sagging expected during operation.The greater friction radius of the prior art bushings results in a muchhigher degree of friction compared to the bushing of the invention.These two features each effects a considerable improvement by itself butonly by their combination as in the present invention is the problem offriction truly and effectively solved.

In one embodiment of the invention, the projecting abutment center isformed by a bulge in the center of the bushing closed end which providesa substantially point-shaped abutment surface for the trunnion and thefriction is reduced to the lowest possible value.

In another embodiment of the invention, the area of the bushing closedend surrounding the projecting abutment surface is substantially planarwhich has a desirable effect on the spring characteristics of the closedend of the bushing.

In a third embodiment of the invention, the bushing closed end isprovided in the area of the projecting 1 abutment face with at least onegroove or depression for receiving lubricant to improve the lubricatingconditions between the trunnion end face and the bushing closed end andthis improved lubrication also reduces the friction.

Referring now to the drawing The FIGURE is a partial cross-sectionalview through a universal joint provided with a bearing bushing of theinvention.

The shaft 1 of the universal joint is provided at its end with a forkedarm 2 having a bore 3 therein in which is mounted a trunnion 4 of theuniversal joint spider 5. The trunnion 4 is accommodated by thin-walled,sheet metal bushing 6 on which needle rollers 7 roll. The bushing 6 canbe fixed in bore 3 by various means such as by expanded ring 8. Theclosed end 9 of bushing 6 has at its center a pressed-down area 10 whichforms on the bushing interior the sole abutment face for the trunnionend face. In the vicinity of the area 10, the closed end 9 of thebushing 6 is substantially planar. The distance between the interiorabutment face 10 and the rest of the closed end 9 is selected so thatthe trunnion end face will abut only in area 10 even with the possibledistrotion of closed end 9 which can occur during assembly and operationof the universal joint. The center of abutment face 10 is provided witha depression 11 for receiving lubricant.

The bearing bushing can be used in roller bearings are well as a slidingbearing wherein the bushing itself or an insert of suitable slidingproperties in the bushing is the bearing surface. The size of theabutment face of the closed end of the bushing will depend upon the loadand the speed that can occur in operation of the universal joint. If thebushing closed end is provided with a central bulge, the abutting facecan be reduced so that practically only a point shape contact takesplace.

Various other modifications of the bearing bushing of the invention maybe made without departing from the spirit or scope thereof and it shouldbe understood that the invention is to be limited only as defined in theappended claims.

We claim:

1. A bearing bushing for accommodating the trunnion of a universal jointspider comprising a thinwalled, sheet metal bushing with one closedradial end opposite the end face of a spider trunnion, the closed radialend being provided in its center with an inwardly directed projectionadapted to abut against the trunnion end face.

2. A bushing of claim 1 wherein the inwardly directed projection isformed by a bulge in the closed radial end 5 of the bushing.

3. A bushing of claim 1 wherein the closed radial end lubricant.

1. A bearing bushing for accommodating the trunnion of a universal jointspider comprising a thin-walled, sheet metal bushing with one closedradial end opposite the end face of a spider trunnion, the closed radialend being provided in its center with an inwardly directed projectionadapted to abut against the trunnion end face.
 2. A bushing of claim 1wherein the inwardly directed projection is formed by a bulge in theclosed radial end of the bushing.
 3. A bushing of claim 1 wherein theclosed radial end surrounding the inwarding directed projection issubstantially planar.
 4. A bushing of claim 1 wherein the closed radialend is provided with at least one groove or depression in the area ofthe inwardly directed projection for receiving lubricant.